The easiest is to set up a free photo hosting site like photobucket.com which is popular.
Open a free account there.
Put the photos you want to post on your desktop.
then select UPLOAD on the photobucket.com site
then drag and drop the photos from your desktop into the big box
after they automatically upload, click on the photo and it will appear in a new window that shows the links
Copy the entire IMG Code for each photo which is what you want to post in the forum - it will look like this
[ img] http ://i%20274. photo.com/albums/ jj259/alasandmdriverknowtheirchopperst/ DSC99869. jpg [/img]
Then paste this link into your post.
IT MUST HAVE THE [ ] brackets on each end.